Safety abrasive wheel and arbor flange



May 23, 1950 R. H. HOFFMAN 2,508,946

SAFETY ABRASIVE WHEEL AND ARBOR FLANGE Filed Nov. 28, 1947 Patented May 23, 1950 UNITED. STATES. PATENT SAFETY'. ABRASIVE WHEEI'L ARBQR.- FLANGEv7 RbbertiH- Hoffman, es'Pl'aiies, lil.

ApplicationY November' 28, 19417:', S'erialaNm 78827239V 1-- Gleim: (Cl. S15-1685),"

The invention, in general, relates to improvements` ini abrasive wheelsl usedin the'Y abrasive arts: andiV relating in this instance to4 abrasive; Wheels which are providedwith mounting anges" tted `to an arbor shaftandL from' which' rotary motion is. derive olf;- but more particularly to` abra'- sive Wheels ofthis type, which: are: provided with' an abrasive annulus; embodying novel safety features, and has for itsobjects: the provisionof' a-device of this character'which vvillX be'- simple of.; construction; economical to manufacture; and-` highlyf eiicient.- in. use.V

Other obj eets.` Will hereinafter appear.

The invention. consists inl the` combinations and. arrangements ot parts hereinafter described and claimed..

The; invention will' be. best understood by reference; to the. accompanying drawings form'-r ing a part of. this. speciiication and` in which- Figure l is a side elevation of. my;`r improved abrasive; wheel and'. arbor Harige embodying my invention and. as; arranged for: use

FigurefZ is aiace View.: of FigureV 11;

Figure 3 is an enlarged' crosssectionview taken on the line. 3-3 ofv Figure l;

Figure 4 is a Side View of an arbor ange serving to connect one sideor tliea'nnulus with the arbor shaft;4 and Figure 5 is a cross section taken' on line Sr-5 of Figure 4.

It is to beY here' note'd'tliat the ri'm flanges 2? being parallel form opposed seats for thering gaskets-3Lsho\vn in.Figs. candi 6i. The'parallel faces: 29. carried. by.. the. arbor: flanges I 9 andthe walls 21. of, the annulusare. placedin frictional engagement by. compression.. of: the'` ring gaskets 3|-,` the circular. groove. carried.v by the annulus 20. is held` out. of, engagement with.v the circular ribv 35 but in radiallalignmenti-by. positionsrelativey toY the, inner` circumference@ 26" of thee an-.- nulus by suitably spaced. arrangement of parts therefor. The ribs 3'0- carried' by each of the angesaZl further serve toif'o'rm' the inneredgeof: the seat for the ring gasketfl in thee-vent that. the .annulus 20,- Whichitssnugly overthe perimeter of the felloe 24 is fractured While in rotary motion the broken portions of the annulus will rnove radially into obstructive engagement with its respective ring portion. It therefore is of advantage that the space between the circular rib and the walls of the groove 28 be of such proportion that expansion of the parts will not cause the ribs 30 to contact the Walls of the groove 28 due to heat developed While in use.

2f The embodiment ofi thev inventionvas illustratfedik in. the drawings cornpri'ses` an arbor. shaft l5 having. ar fixed`- collar I'6`.. an'd`a. threadedend por-V tion l1? equipped with a threaded nutlil.. The:

arbor shaft'. I'5'V is providedl with. two-similarly constructsdand-oppositely arranged arbor flanges Ig mounted' inspaced' relation. and interceptedl by an abrasive annulus 20'. of' integral. construction. The annulus 205 isfheld in. clamped?en-k gagement and rotatable. with vthearbor Shaft IE by means of the arbor anges T9 whendrawn. into irictionalcontact by means of` the .threaded r111t` I8.

Yinner 'face with'. an inwardly projecting' wheel? like prominence'having sii'r concavitie's 2'I oi's'i'rnt lar size an`d"sl`i`ape arrangdradilly 'irvs'laced and' circular relation.' The arrangement of tHe.' concavities: 2i' concentricv with." the arbor shaft.' i s isV suc-hetnet awneer like prominence 'isiforined' on the inner face'ofe'a'c'h' arbor. ang'e 9"Wh1bflf comprises' a -hub 22; spokes" 23; and"`a` 'flloe 2E* having" a' perimeter' 25, in c'erit'e'red"'aligni'rie'iV tnerewitha The periirleter- 25 of" the "felle' 2'6" of" each arbor flange' ISi'isof. a' siz"e"an`d"sli'ap"e"tb fit' freely'Y yet snugly' against the"inne`r"circn ferential Wall 26"o`f"the^a'nnulus 2 IJ. Y 2U,- which' may'l be"ooiistru'cted of: any sutabl' abrasive' material, is1 of integral form' having' straightand'- parallel* sidewalls 2-rl eaclrprovitl'e'cvv with a" circulargroove`28of semi-'circular cross" section 'arrangedadjaoent'tne innereirtuinierenu tial wall' 26", asi bestl shown iirF'iguref'Si 1 Aextending outwardly from'l tile inn-er edge ofthe* iell'o'e 24 inr paralleli'a'nd* spaced relati'on`ti`ik itis4 adjacent side walls 2l' of the annulus 20, in assembled position-i fory use. Itis tobeliere notedith'at theY rim-flanges 2'9ibein'g` parallel;form opposed* seats for' theriiig4v gaskets 3132 shown' in* nulus are placed in"fricior`ial engagementl compression ofL the ring'vl gaskets; .'g'i the; circular groove carriedby= thea annulus 2 (l`lis'i held out f of'j engagement with the circular rib 30 but in radial alignment by positions relative to the inner circumference 26 of the annulus 20 by suitably spaced arrangement of parts therefor. The ribs 30 carried by each of the flanges 29 further serve to form the inner edge of the seat for the ring gasket 3|, in the event that the annulus 20, which fits snugly over the perimeter 25 of the felloe 24 is fractured while in rotary motion the broken portions of the annulus will move radially into obstructive engagement with its respective ring portion. It is therefore or advantage that the space between the circular rib 30 and the walls of the groove 28 be of such proportion that expension of the parts will not cause the ribs 30 to Contact the walls of the groove 28 due to heat developed while in use.

The rim ange 29 is provided centrally with an inwardly projecting circular rib 38 of approximately semicircular cross section of a shorter diameter than that of the circular groove 28 with which it is centered in transverse alignment, .as best shown in Figure 3. Each of the rim flanges 29 is further provided on its inner face with a shallow dat bottomed channel 33 arranged concentrically and contiguously with the circular rib 38 serving the purpose when mounted of providing a circular yrecess 34 to allow for .lateral expansion without constraint of the inner- Amost portion of the annulus 28.

A suitable flat ring gasket 3l cut from sheet material such as neoprene, rubber or other suitable plastic like material of a thickness sufficient for the purpose, is mounted outwardly of the circular rib 30 on the rim iiange 29 in frictional contact with the side wall 27 of the annulus 20 and outwardly of the circular groove 28. Attention is directed particularly to the thickness of the gasket Si, its position of contact with the side wall 2l, and the location of the rib 30 arranged within the confines of the groove 28 and out of contact with the walls thereof. The arrangement of the annulus 20 on the perimeter 25 serves only the purpose of the centering of it relative to the arbor shaft l and serves but little to prevent relative rotation due to the drag on the outer circumference 32. The inner portion of the annulus 28, adjacent the inner circumferential wall 28, is thus freed to a great extent of the radial stress; and by applying the gasket 3'! to the side wall 2 outwardly of the circular groove 28 a reserve area is provided greatly increasing the margin of safety.

The arrangement of the circular grooves 28 of the annulus 20 with the circular ribs 30 of the arbor flanges IS is such that the central portion of the annulus 20, inwardly of the area contacted by the ring gasket 3 I, is substantially free of side pressure and strain resulting therefrom, the ribs 30 being out of contact with the wall of the groove 28. In the event that a radial fracture of the annulus 28 should accidentally occur while it is in motion the fragments would be moved outwardly by centrifugal force into contact with the circular rib 38, as will be readily understood.

The side walls 27 of the annulus 20 are each provided with at least one circular groove 28, and each arbor flange i9 is provided an attendant circular attendant rib 38 for each groove 28. When the device is in assembled position, as best shown in Figures 3 and 6, the relative radial width of. a groove 28 or 36 (Figure 6) to that of its attendant circular rib 30 or 35 (Figure 6) is such that a recess 34 is provided. While one groove 28 and one rib 30 is shown on each side wall 21 in Figure 3 these may be increased in number and relative widths dependent on the relative 5 tensile strength of each. Should a plurality of groove and attendant ribs be used these may be graduated in size and varied in arrangement either for instant contact or for consecutive contacts after the fracture of the annulus, as will be readily understood.

While I have illustrated and described the details of a practical embodiment of my invention these may be modified, altered, rearranged, and otherwise changed without departing from the pronounced innovations herein; I, therefore, do not wish to be limited to the precise details set forth but seek to avail myself of such variations and modiiications as may fall within the spirit and scope of the following claim.

I claim:

An abrasive wheel assembly comprising. a sup-A porting shaft, a pair of opposed clamping members clamped upon said shaft and an abrasive wheel supported by said clamping members, said clamping members each having a central hub portion dening wheel-supporting portions which extend into the arbor hole of the grinding wheel and opposed lip portions extending radially beyond said hub portion and parallel to the sides of the abrasive wheel, each of said lip portions having a concentrically arranged annular recess adjacent the hub portion and extending axially into said lip portion, an annular concentrically arranged bead adjacent said recess and extending axially into a complementary annular groove in each of the sides of said abrasive wheel and a iiat annular portion extending radially beyond said bead and extending adjacent to and parallel to the sides of the Wheel and rmly gripping the wheel, the beads on the clamping members constituting safety means for preventing pieces of the wheel from being thrown from the assembly in case of rupture of the wheel.

ROBERT H. HOFFMAN.

REFERENCES CITED The following references are of record in the' file of this patent:

UNITED STATES PATENTS Name Date Suwerkrop Mar. 22, 1870 Church Sept. 6, 1870 Henry Apr. 21, 1874 Robinson Apr. 2, 1878 Ware July 19, 1881 Alden et al Sept. 1, 1896 Williams May 1, 1900 Clark Oct. 21, 1941 FOREIGN PATENTS Country Date France Nov. 20, 1912 Switzerland Feb. 17, 1936 Number 

